Aeronáutica

URI permanente para esta comunidadhttps://digitalpro.inta.es/handle/20.500.12666/37

Muchas de las líneas de investigación del INTA se centran en el ámbito aeronáutico. Estas líneas van encaminadas a reforzar las competencias en nuevas tecnologías, haciendo especial hincapié a las relacionadas con caracterización de emisiones producidas por turborreactores, investigación en tecnologías del hidrógeno y otras energías renovables, motores cohete con propulsante líquido y sólido, estudio de materiales funcionales, diseño y fabricación de superficies hielofóbicas, recubrimientos protectores para la corrosión por biomasa, estructuras activas avanzadas y robótica, generación avanzada de trayectorias sobre UAVs, aprendizaje automático e inteligencia artificial sobre minería de datos aerodinámicos y actuadores de plasma y sus aplicaciones.

La investigación de la Aeronáutica se materializa en proyectos financiados con fondos propios, como por ejemplo GERD, que trata del estudio de las condiciones y las tipologías de formación de hielo en superficies. Actualmente se están finalizando las tareas de implementación del nuevo de viento de engelamiento, único en el país, duplicando la capacidad de realización de ensayos en condiciones de formación de hielo.

En el sector aeronáutico del INTA cabe destaca el CIAR, un centro de ensayos en vuelo innovador, que proporciona apoyo técnico y logístico en la experimentación de sistemas de vuelo no tripulados en el ámbito de operación civil o dual y el CEDEA, un centro de ensayos para caracterización de aeronaves y sus componentes tanto tripuladas como no tripuladas, experimentación de misiles, cohetes e I+D de proyectos aeronáuticos de energía y estudio de la atmósfera.

Otros campos de investigación relacionados con la Aeronáutica son la tecnología del vuelo, la aerodinámica teórica y experimental, materiales y estructuras, desarrollo de pinturas, estudio de nuevas fuentes de energía, con programas de I+D dentro del campo de la propulsión y de su aplicación aeroespacial, estudio del impacto medioambiental de los propulsantes y trabajos relacionados con los combustibles y lubricantes en el ámbito aeroespacial y de la Defensa Nacional.

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Mostrando 1 - 20 de 31

Acceso Abierto
10,000 h molten salt corrosion testing on IN617, uncoated and aluminide ferritic steels at 580 ºC
(Richter C., 2020-12) Agüero, Alina; Audigié, P.; Rodríguez, Sergio; European Commission (EC)
Long term testing of two ferritic-martensitic steels (P91 and VM12-SHC) with and without slurry deposited aluminide coatings containing 20 wt.% of Al at the surface was carried out by exposing these materials to the Solar Salt, a eutectic mixture composed of 60 % NaNO3 - 40 % KNO3 at 580ºC. This salt is currently used in operating thermal solar power plants as heat transfer and storage fluid. Tubes made of expensive Ni based alloys are employed to mitigate corrosion. The tested uncoated ferritic materials exhibited very high corrosion rates developing thick, easily detached scales. IN617 was also tested as a reference and experienced very low corrosion up to 5,000 h, but after 10,000 h a 50 ȝm thick, mostly NiO scale had developed with Na0.6CoO2 crystals deposited on top. There was also evidence of significant Cr depletion at the alloy surface. Carcinogenic CrVI was found in the Solar Salt melt in which the three uncoated alloys were immersed. In contrast, the two coated ferritic steels did not show evidence of degradation after 10,000 h and the most significant microstructural change was the development of a very thin protective NaAlO2 layer on their surface. An industrial process to deposit these coatings on the inner surfaces of pipes has already been developed.
Acceso Abierto
A slurry coating for Cd replacement for aircraft components
(Mondragon Unibertsitatea, 2008-07-25) Agüero, Alina; Blanco, C; Gutiérrez del Olmo, Marcos; García Martínez, María
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Al Slurry Coatings for Molten Carbonate Fuel Cell Separator Plates
(Scientific.Net, 2001-01-20) Agüero, Alina; García, M. C.; Muelas Gamo, Raúl; Sánchez, A.; Pérez, Francisco J.; Duday, David; Hierro, M. P.; Gómez, Consuelo
The corrosion behaviour of Al slurry coated AISI 310 stainless steel, with and without diffusion heat treatment, was investigated as a wet seal material for molten carbonate fuel cell (MCFC) at 650°C. The results were compared with IVD Al coated AISI 310. Characterization of the samples before and after exposure to the eutectic 62 mol% Li2CO3-38 mol% K2CO3 mixture at 650°C for 1000 h by SEM-EDS and XRD was carried out. The presence of LiAlO2 on the coated samples was confirmed by XRD. The slurry Al-coated stainless steels performed at least as well as the IVD Al coating.
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Comparison between field and laboratory steam oxidation testing on aluminide coatings on P92
(Wiley online library, 2011-01-12) Agüero, Alina; González, V; Gutiérrez del Olmo, Marcos; Knödler, R; Straub, S; Muelas Gamo, Raúl; Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Steam oxidation has become an important issue for steam power plants as operating temperatures increase from the current 550 to 600–650 °C. For the last 10 years several groups have been carrying out steam oxidation testing of both uncoated substrates and coatings in the laboratory. On the other hand, field testing results are very scarce. In this paper, a comparison of laboratory steam oxidation testing with field test results carried out by Alstom at the Kraftwerk Westfalen power station located in Hamm, Germany will be presented. Both slurry deposited aluminide coatings and uncoated P92 steel have been included in the study. Under steam (atmospheric pressure) and isothermal conditions in the laboratory at 650 °C, spallation of oxides formed on ferritic steels occurs after significantly longer time when compared to exposure to real operating conditions. Oxide spallation results in serious damage in steam power plants by obstructing heat exchanger tubes, erosion of valves and turbine blades, etc. Moreover, the thickness of the oxide scales formed under field testing conditions is significantly higher after similar exposure. On the other hand, aluminide coated P92, which exhibit thickness through cracks, have shown to be stable in the laboratory for up to 60 000 h at 650 °C under steam, without evidence of crack propagation. However, field test results indicate that some degree of crack propagation occurs but without causing substrate attack up to 21 700 h of exposure. Moreover, the aluminium oxide observed in both laboratory and field tested specimens is different.
Acceso Abierto
Comparison between pilot and lab scale testing of aluminide coated and uncoated ferritic steels under oxy-fuel and coal/thistle co-firing conditions
(Elsevier, 2022-11-25) Gutiérrez, M.; Illana, Andrea; Bahillo, Alberto; Benito, Manuel J.; García Martín, G.; Pérez Trujillo, Francisco Javier; Agüero, Alina; European Commission (EC); Universidad Complutense de Madrid(UCM)
The present study compares the biomass corrosion behavior of two diffusion aluminide coating obtained by slurry application, which were deposited on two low-chromium content steels, ferritic-martensitic P92 (8.7 wt% Cr) and ferritic T22 (2 wt% Cr). Their performance degradation was conducted under an oxy-fuel combustion environment for both coated and uncoated materials both under laboratory conditions and in a pilot plant burning thistle for 500 h. Exposures were carried out in the laboratory at two different temperatures, 600 °C and 650 °C, under a model atmosphere consisting of 60 % CO2, 30 % H2O, 8 % O2, bal.% N2 (in vol%), 500 vppm HCl and 2 vppm SO2. The pilot plant used a mixed fuel of 60 wt% coal and 40 wt% thistle that was burnt and the samples were exposed to a temperature range of 600–620 °C. After testing, the results revealed that the aluminide-coated materials exhibited a very high resistance under both extreme scenarios, with a variable protective character related to their Al content. On the contrary, uncoated material exhibited severe degradation, in particular T22. Microstructural and morphological studies showed up similar corrosion patterns and products on coated and uncoated materials for both testing environments.
Restringido
Cyclic oxidation and mechanical behaviour of slurry aluminide coatings for steam turbine components
(Elsevier, 2007-04-02) Agüero, Alina; Muelas Gamo, Raúl; Gutiérrez del Olmo, Marcos; Van Vulpen, R.; Osgerby, Steve; Banks, J. P.
The excellent steam oxidation resistance of iron aluminide coatings on ferritic steels at 650 °C has been demonstrated both by laboratory tests and field exposure. These coatings are formed by the application of an Al slurry followed by diffusion heat treatment at 700 °C for 10 h. The resulting microstructure is mostly composed of Fe2Al5 on top of a much thinner FeAl layer. This coating exhibits perpendicular cracks due to thermal expansion mismatch between coating and substrate. However, these stress relieving cracks do not seem to have an effect on the mechanical properties of the substrate. Cyclic oxidation, creep resistance and TMF testing of these coatings at 650 °C indicate excellent performance.
Restringido
Deposition process of slurry iron aluminide coatings
(Taylor and Francis online, 2008-10-04) Agüero, Alina; Gutiérrez del Olmo, Marcos; González, Vanessa
Diffusion iron aluminide coatings prevent steam oxidation of ferritic/austenitic steels at 650°C for at least 45,000 h. These coatings are deposited by applying Al slurries followed by a diffusion heat treatment at 650°C. The quality of the coatings is very sensitive to a number of factors such as surface preparation, slurry composition and diffusion treatment temperature. A study of the effect of the different processing parameters has been performed in order to optimize the process from an industrial perspective. Moreover, most commercially available Al slurries contain different levels of Cr6+, a highly carcinogenic species, and therefore Cr6+ free slurry formulations have been prepared. In addition, re-coating after exposure has also been developed since it is not clear yet if these coatings will last the 100,000 h which is the life limit for steam power plant design. Based on these studies, processes suitable for coating real size components and re-coating steam exposed components have been developed and are presented in this contribution.
Acceso Abierto
Development and Qualification of New Solid Lubricant Coatings. A Tribology Experiment at the Tribolab onto EUTEF
(Centre national d'études spatiales (CNES), 2000-06-12) Oñate, J. Ignacio; Brizuela, Marta; García Luis, Alberto; Viviente, J. Luis; García de Blas, Javier; Agüero, Alina; Longo, Federico; Román, Alicia
A recent study has identified that a significant number of satellite failures and anomalies, including those caused during qualification testing of mechanisms, were caused by lubrication related problems. Solid lubrication is, owing to lower vapour pressures, better boundary lubrication properties, relative insensitivity to radiation effects and wider temperature range of operation, still a preferred option for a number of space mechanisms. However, actual solid lubricants wear out and do not provide effective protection for long life mechanisms. A longer life and reduced wear debris is desirable to improve mechanism reliability. The present work reports on early results on the development of a new generation of solid lubricant coatings by the use of state of the art magnetron sputtering technology and thermal spraying processes. These coatings after a proper qualification procedure under laboratory ground conditions will be finally tested at the TriboLAB instrument that will be integrated onto the EuTEF facility at the International Space Station (ISS). Metal alloyed MoS2 solid lubricant films have been produced by a magnetron sputtering PVD process. Tribotests carried out under vacuum in a ball-on-disc tribometer with MoS2 coated AISI 440C steel discs have shown very low friction coefficients of 0.01 and long endurance, in excess of 300,000 revolutions at about a max. 0.8 GPa contact stress. These films also exhibited low friction coefficients (about 0.10) and good durability under atmospheric conditions at RT and up to 50 to 60 % RH. The thick composite lubricant coatings consisting of AlCoFeCr, NiCr, Ag and BaF2-CaF2 were deposited by plasma spray and HVOF on X-750 Ni-base superalloy. These coatings have been characterised by EDS-SEM as well as hardness measurements. The best coatings from preliminary experiments have been produced by HVOF process; these show very low porosity, a more uniform phase distribution and hardness levels of 635 HV0.2. Anticipated high temperature applications of former coatings might include elevon hinges for re-usable space planes.
Acceso Abierto
Development and Validation of Advanced Oxidation Protective Coatings for Super Critical Steam Power Generation Plants
(Grafische Medien, 2006-07-06) Scheefer, M.; Bernard Henderson, Michael; Agüero, Alina; Allcock, B.; Norton, B.; Tsipas, D. N.; Durham, R.; European Commission (EC)
Increasing the efficiency of coal-fired power plant by increasing steam temperatures and pressures brings benefits in terms of cheaper electricity and reduced emissions, particularly CO 2 . In recent years the development of advanced 9%Cr ferritic steels with improved creep strength has enabled power plant operation at temperatures up to 600 -620ºC such that these materials are currently being exploited to construct a new generation of advanced coal-fired plant. However, the move to higher temperatures and pressures creates an extremely hostile oxidising and errosive environment. To enable the full potential of the advanced 9%Cr steels to be achieved, it is vital that protective coatings are developed, validated under high pressure steam environments and applied successfully to candidate components from the high pressure steam path. This paper reviews recent work conducted within the Framework V Brite EuRam project "Coatings for Supercritical Steam Cycles" (SUPERCOAT) to develop and demonstrate advanced slurry and thermal spray coating technologies capable of providing steam oxidation protection at temperatures in excess of 620°C and up to 300 bar pressure. The programe of work described has demonstrated the feasibility of applying a number of candidate coatings to steam turbine power plant components and has generated long-term steam oxidation rate and failure data that underpin the design and application processing work packages needed to develop and establish this technology for future and retrofit plant.
Acceso Abierto
Experience with 9Cr3W3CoVNbBN base material and crosswelds at 650°C for implementation in USC power plants
(National Institute for Materials Science, Tsukuba , Japan, 2009-06-14) Mayr, Peter; Mendez Martín, Francisca; Holzer, Iván; Agüero, Alina; González, Vanessa; Baumgartner, Susanne; Cerjak, Horst Hannes
This manuscript gives an overview on recent developments of a martensitic steel grade based on 9Cr3W3CoVNb with controlled additions of boron and nitrogen. Alloy design by thermodynamic equilibrium calculations and calculation of boron-nitrogen solubility is discussed. Two melts of a 9Cr3W3CoVNb steel were produced. The oxidation resistance was examined at 650°C in steam atmosphere. The alloy exhibited high resistance to steam oxidation at 650°C for at least 5.000 hours of exposure. Microstructural evolution during welding within the heat-affected zone was investigated by physical weld simulation, thermo-dilatometry and in situ X-ray diffraction using high energy synchrotron radiation. The heat-affected zone microstructure is characterized by optical microscopy. Two multilayer welds, one with a nickel based filler and one with a newly developed flux cored filler of matching chemical composition, were fabricated. All weldability experiments showed that within the heat-affected zone the initial base material microstructure is retained to a large extent. The formation of a uniform fine-grained heat-affected zone region is suppressed. Uniaxial creep tests of base material, weld metal and crossweld specimens were started at different levels of stress at 650°C. Up to the established maximum testing time of 20.000 hours, the base material shows significant improvement compared to standard 9 wt. % Cr grades P91 and P92. Crossweld specimens show an improved strength level, higher than that of grade P92 base material. Preliminary results of an extensive testing program on a 9Cr3W3CoVNbBN steel show significant improvement compared to the state-of-the-art 9 wt. % Cr martensitic steel grades.
Acceso Abierto
High velocity oxy-fuel (HVOF) coatings for steam oxidation protection
(European Federation of Corrosion Publications, 2011-07-22) Agüero, Alina; Muelas Gamo, Raúl; González, Vanessa
Introduction European COST Actions 522 (completed in 2003) and 536 (ongoing) have concen-trated on designing and producing steels for steam power plants capable of operating at 600–625 °C in order to increase effi ciency and reduce emissions [1–4]. However, efforts to produce ferritic steels for turbine components capable of operating at temperatures of 625 °C or higher have not yet been successful [5]. Materials such as P92 and COST-developed CB2 (9 wt.% Cr) with high creep strength up to 625 °C, have unacceptable oxidation resistance (Fig. 6.1), whereas materials with higher Cr content such as COST-developed FT4 (11 wt.% Cr) have better oxidation resistance but lower creep strength. When exposed to high-pressure steam at these tempera-tures, ferritic steels develop thick oxides which spall after relatively few hours of exposure [6]. Cross-section reduction, blockage and component damage due to erosion caused by the spalled oxides are some of the possible consequences. A similar situation occurred with power generation and aeronautical gas turbines 45 years ago, when efforts to develop superalloys with the required mechanical properties as well as very low oxidation rates resulted in failure at higher operating temperatures. The solution was to employ coatings on superalloys with the required mechanical properties and presently, all new generation gas turbines require high-temperature oxidation resistance coatings as well as thermal barriers [7]. In 1998, efforts to examine the feasibility of applying coatings to steam turbine components were carried out within the context of COST 522 [8]. The results were very promising and the work continued within the framework of the European Commission project 'Coatings for Supercritical Steam Cycles' (SUPERCOAT) in which eight partners from different organisations across Europe participated [9,10]. A number of coatings, applied by means of slurry deposition, pack cementation and High Velocity Oxy-Fuel (HVOF) thermal spray were subjected to a variety of tests, including steam oxidation, creep strength, thermo-mechanical fatigue, etc. The project has recently been completed and some of the explored coatings were down-selected as candidates for industrial scale application on real components and for validation. * Reprinted from A. Agüero et al.: HVOF coatings for steam oxidation protection. High velocity oxy-fuel (HVOF) coatings for steam oxidation protection 53 Among the explored coating techniques, chosen on the basis of being potentially appropriate for coating large steam turbine components, HVOF thermal spray has emerged as one of the most successful. Abe and co-workers have also studied a number of HVOF deposited materials for this application [11]. This paper describes the steam oxidation behaviour of several alloyed materials deposited by this technique including the characterisation of the protective oxides formed on each material.
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Hot corrosion study of coated separator plates of molten carbonate fuel cells by slurry aluminides
(Elsevier, 2002-12-02) Pérez Trujillo, Francisco Javier; Duday, David; Hierro, María Pilar; Gómez de Castro, Consuelo; Agüero, Alina; García, M. C.; Muelas Gamo, Raúl; Sánchez Pascual, A.; Martínez, L.
The corrosion behavior of Al coated AISI 310S stainless steel by slurry and ion vapor deposition (IVD) was investigated as an electrolyte seal material in a mounted carbonate fuel cell (MCFC) at 650 °C. The results were compared with uncoated AISI 310S stainless steel and TA6V alloy. The characterization of the samples after exposure to the eutectic 62 mol.% Li2CO3–38 mol.% K2CO3 mixture at 650 °C up to 1000 h has shown the presence of LiAlO2 (coated samples), LiFeO2 and LiCrO2 (stainless steels), and Li2TiO3 (TA6V) oxides at the scale–melt interface. The electrochemical impedance spectroscopy (EIS) technique has shown high values of polarization resistances for TA6V and lower values for coated steels. The uncoated AISI 310S stainless steel have shown the lowest polarization resistance. A mechanism for the corrosion of Al-coated stainless steels in molten carbonate is proposed taking into account thermodynamic simulations, X-ray diffraction (XRD), scanning electron microscopy (SEM) characterizations, and EIS results. This proposed mechanism confirms that a slurry aluminide coating is able to improve the stainless steel behavior in molten carbonate. However, the TA6V titanium alloy is the most resistant material in molten carbonate but the Al-coated stainless steels appear as the best lifetime-cost compromise.
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HVOF coatings for steam oxidation protection
(Wiley online library, 2008-05-29) Agüero, Alina; Muelas Gamo, Raúl; González, Vanessa; Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
In the context of the European project ‘Coatings for Supercritical Steam Cycles’ (SUPERCOAT), the use of steam oxidation resistant coatings on currently available ferritic materials with high creep strength but poor oxidation resistance was investigated in order to allow increase in the operating temperature of steam power plants from 550 to 650 °C. Among the explored coating techniques for this application, chosen on the basis of being potentially appropriate for coating steam turbine components, High Velocity Oxy Fuel (HVOF) thermal spray has resulted in one of the most successful techniques. Different alloyed materials such as FeCrAl, NiCrSiFeB, FeAl, NiCr and FeCr have been deposited, optimized and tested under flowing steam at 650 °C. Characterization of as deposited and tested samples by metallography, SEM-EDS and XRD was carried out. Some of these coatings form protective pure chromium or aluminium oxides exhibiting excellent behaviour for at least 15 000 h of exposure, whereas others form less stable complex mixed oxides which nevertheless grow at considerably slower rates than the oxides formed on uncoated P92 (9 wt% Cr ferritic steel).
Acceso Abierto
Improved Creep and Oxidation Behavior of a Martensitic 9Cr Steel by the Controlled Addition of Boron and Nitrogen
(University of Liege, 2010-09-27) Mayr, Peter; Holzer, Iván; Mendez Martín, Francisca; Albu, Mihaela; Mitsche, Stefan; González, Vanessa; Agüero, Alina
Acceso Abierto
Ingeniería de Superficies y Medioambiente
(Universidad Complutense de Madrid, 2006-01-06) Agüero, Alina
Acceso Abierto
Laboratory intercomparison of solar absorptance and thermal emittance measurements at room temperature
(Elsevier, 2022-05-14) Caron, Simon; Herding, L.; Binyamin, Yaniv; Baidossi, M.; Vinetsky, Y.; Morales, Angel; Hildebrandt, C.; Reoyo Prats, R.; Faugeroux, O.; Agüero, Alina; Rodríguez, Sergio; Sutter, Florian; Röger, M.; Manzano Agugliaro, F.; European Commission (EC)
Solar thermal absorber coatings play an important role in the opto-thermal efficiency of receivers in Concentrated Solar Power (CSP). Two standard figures of merit are the solar absorptance αsol and thermal emittance εth, derived from spectral directional hemispherical reflectance measurements at room temperature. These two figures of merit allow comparing coating formulations in terms of performance and durability. In this study, a black coating and a solar selective coating are optically characterized by different laboratories to compare spectral datasets, solar absorptance αsol and thermal emittance εth calculations. The comparison includes various benchtop spectrophotometers operating in the UV-VIS-NIR and Infrared spectral ranges as well as three commercial portable reflectometers/emissometers. A good agreement is found between the nine parties participating in this intercomparison campaign. The black coating αsol value is 96.6 ± 0.2%, while the solar selective coating αsol value is 94.5 ± 0.4%. For the thermal emittance, spectral data is concatenated and integrated from 0.3 to 16 μm. The black coating εth value calculated at 650 °C is 80.8 ± 3.8%, while the solar selective coating εth value calculated at 650 °C is 25.0 ± 0.5%.
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Long exposure steam oxidation testing and mechanical properties of slurry aluminide coatings for steam turbine components
(Elsevier, 2005-11-21) Osgerby, Steve; Pastor Muro, Ana; Agüero, Alina; Muelas Gamo, Raúl
Important efforts to develop new steels or to protect high creep strength steels in order to allow operation of steam turbines at 650 °C are being carried out world-wide to increase efficiency. Within the European Project “SUPERCOAT” (Coatings for Supercritical Steam Cycles), work has been concentrated in the development of coatings to withstand 50,000–100,000 h of operation at 650 °C under high pressure steam. Aluminide coatings on ferritic–martensitic steels produced by applying an Al slurry followed by a diffusion heat treatment, have shown to be protective at 650 °C under steam for at least 32,000 h of laboratory steam exposure under atmospheric pressure. Although the “as diffused” coatings present through thickness cracks, these do not propagate during exposure to steam or thermal cycling and no new cracks seem to develop. Moreover, no changes in residual stresses could be observed after thermal cycling. Microstructural characterization of samples at different periods of exposures has been carried out by SEM-EDS and XRD. The principal mechanism of coating degradation is loss of Al at the surface due to inwards diffusion. Microhardness as well as Young's modulus and fracture strength were measured using well established techniques. The coatings show reasonable ductility (∼1.6%) when stressed in tension between room temperature and 400 °C which further increases at higher temperatures providing evidence that the coatings should withstand the mechanical conditions likely to be encountered in service.
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Long term diffusion studies in Fe aluminide coatings deposited by slurry application on ferritic steel
(Scientific.Net, 2009-04-22) Agüero, Alina; González, Vanessa; Gutiérrez del Olmo, Marcos
Diffusion iron aluminide coatings have shown excellent resistance to high temperature oxidation in air, corrosive atmospheres and steam. A study of the diffusion behaviour of slurry applied diffusion aluminide coatings deposited on ferritic steel have been carried out under a 100% flowing steam atmosphere for up to 50,000 h at 650 °C. The results have shown that initially, the coating forms by outward growth possibly including the dissolution of the steel in molten aluminium. At later stages, during exposure to steam at 650 °C, aluminium diffuses inward and moreover, Fe also diffuses outward resulting in the progressive development of Kirkendall porosity. Results have also indicated that in order to form a pure protective Al2O3 scale the Al wt.% has to be > 4. Below this content Al-Fe mixed oxides develop exhibiting a less protective behaviour.
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Metal Dusting Protective Coatings. A Literature Review
(Springer Nature Link, 2011-03-20) Agüero, Alina; Gutiérrez del Olmo, Marcos; Korcakova, L; Nguyen, T. T. M; Hinnemann, B; Saadi, S
Metal dusting is a catastrophic form of carburization attack that takes place in carbon-supersaturated gaseous atmospheres, and is most commonly encountered in steam reforming processes such as the production of hydrogen or syngas for ammonia, Fischer–Tropsch and methanol applications. The consequence of metal dusting can be a severe loss of metal from the process units, leading to high-cost maintenance and serious safety issues. The present literature review discusses the latest developments within metal dusting protection of alloys with special emphasis on protective coatings. In the first part of the paper, an overview of the main theories for metal dusting of alloys as well as fundamental studies is provided. In the second part, the paper focuses on the different methods to prevent metal dusting, including surface poisoning, alloying, chemical, mechanical and laser treatments as well as coatings. Particular focus is given to coatings and their composition, and fabrication methods, and a critical analysis of the different materials’ behaviours and the suitability perspectives of deposition techniques are provided.
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Microstructural Evolution of Slurry Fe Aluminide Coatings during High Temperature Steam Oxidation
(Trans Tech Publications, 2008-09-15) Agüero, Alina; Spiradek, Krystina; Höfinger, S; Gutiérrez del Olmo, Marcos; Muelas Gamo, Raúl
Slurry iron aluminide coatings are very resistant to steam oxidation at 600-650º C. These coatings can be used to protect new generation Ultra Super Critical (USC) steam power plant ferritic/martensitic steel components. The microstructure of the initially deposited coating changes as a function of time, mainly due to coating-substrate interdiffusion, going from mostly Fe2Al5 to FeAl, causing the precipitation of AlN in those substrates containing a minimum content of N and moreover, developing Kirkendall porosity at the coating-substrate interface. Steam oxidation at 650º C causes the formation of a protective thin layer of hexagonal χ-Al2O3 phase along with some α- and γ-Al2O3 after the first few hours of exposure. However, despite the relatively low temperature, and after several thousands hours the protective layer was mostly composed of α-Al2O3. A study of the evolution of the microstructure of slurry aluminide coatings deposited on P92 and exposed to steam at 650º C has been carried out by scanning and transmission electron microscopy and X ray diffraction.

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Examinando Aeronáutica por Autor "Agüero, Alina"